Phthalocyanine crystal, production process therefor, and electrophotographic photosensitive member, process cartridge and apparatus using the crystal

ABSTRACT

An electrophotographic photosensitive member exhibiting a high sensitivity and a potential stability on repetitive use and capable of suppressing image defects, such as black spots in a reversal development scheme, is provided. The photosensitive member includes a support, and a phthalocyanine layer formed on the support and a novel phthalocyanine crystal, which comprises a phthalocyanine compound and a substituted or unsubstituted condensed polycyclic hydrocarbon compound.

This application is a divisional application of U.S. patent applicationSer. No. 09/771,714, filed Jan, 30, 2001, now U.S. Pat. No. 6,447,967.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a novel phthalocyanine crystal, aprocess for producing the phthalocyanine crystal, an electrophotographicphotosensitive member using the phthalocyanine crystal, and a processcartridge and an electrophotographic apparatus including thephotosensitive member.

As photoconductor materials for electrophotographic photosensitivemembers, inorganic photoconductors, such as cadmium sulfide, and zincoxide, have been conventionally used. On the other hand, organicphotoconductors, such as polyvinyl carbazole, oxadiazole, azo pigmentsand phthalocyanine have advantages of non-pollution characteristic andhigh productivity compared with the inorganic photoconductors butgenerally have a low conductivity so that the commercialization thereofhas been difficult. For this reason, various sensitizing methods havebeen proposed, and among them, the use of a unction separation-typephotosensitive member including a charge generation layer and a chargetransport layer in a laminated state has become predominant and has beencommercialized.

On the other hand, in recent years, non-impact-type printers utilizingelectrophotography have come into wide in place of conventionalimpact-type printers as terminal printers. Such non-impact-type printersprincipally comprise laser beam printers using laser light as exposurelight, and as the light source thereof, semiconductor lasers have beenpredominantly used, in view of the cost and apparatus size thereof. Thesemiconductor lasers principally used currently have an oscillatingwavelength in a long wavelength region of 650-820 nm, so thatelectrophotographic photosensitive members having a sufficientsensitivity in such a long wavelength region have been developed.

Phthalocyanine compounds are very effective charge generating materialshaving a sensitivity up to such a long wavelength region, and comparedwith conventional phthalocyanine compounds and polyvinyl carbazole,oxytitanium phthalocyanine and gallium phthalocyanine are known to havebetter sensitivities, and various crystal forms thereof have beendisclosed, e.g., in Japanese Laid-Open Patent Application (JP-A)61-239248, JP-A 61-217050, JP-A 62-67094, JP-A 63-218768, JP-A 64-17066,JP-A 5-98181, JP-A 5-263007 and JP-A 10-67946.

Further, it has been known that a phthalocyanine compound of even asimilar crystal form can exhibit remarkably differentelectrophotographic performances, particularly in sensitivity andchargeability, when used in an electrophotographic photosensitive memberdepending on production process factors, such as starting materials andsolvents, and production conditions, such as reaction temperatures andstarting material charging ratios.

Production processes for gallium phthalocyanine crystals have beendisclosed in, e.g., JP-A 8-100134, JP-A 9-111148, JP-A 9-124967, JP-A10-7927 and JP-A 10-17784. Further, JP-A 7-331107 discloses ahydroxygallium phthalocyanine crystal containing a polar solvent, suchas N,N-dimethylformamide. Electrophotographic photosensitive membersusing these gallium phthalocyanine crystals are liable to exhibit afluctuation in electrophotographic performances depending on productionlots and do not necessarily have satisfactory sensitivity, potentialstability in repetitive use and chargeability in view of requirementsfor higher speed and higher image quality in electrophotography inrecent years.

Further, while having an excellent sensitivity to long-wavelengthregion, an electrophotographic photosensitive member using aphthalocyanine compound is accompanied with difficulties, such asfluctuation in electrophotographic performances depending on productionlots and liability of image defect (sometimes called “black spots”),that is, black spotty fog occurring in a white background region in areversal development system, due to local charge injection, particularlyin a high temperature/high humidity environment. Further, thephotosensitive member is accompanied with a difficulty that itslight-part potential is liable to be fluctuated on repetitive use.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems of the prior art, a principalobject of the present invention is to provide an electrophotographicphotosensitive member exhibiting a high-sensitivity characteristicparticularly in a semiconductor wavelength region, exhibiting a stablepotential characteristic on repetitive used and capable of reducingimage defects, particularly backspots in a reversal development scheme.

A further object of the present invention is to provide a novelphthalocyanine crystal capable of providing such a photosensitive memberand a process for producing the phthalocyanine crystal.

A still further object of the present invention is to provide a processcartridge and an electrophotographic apparatus including thephotosensitive member.

According to the present invention, there is provided a phthalocyaninecrystal, comprising: a phthalocyanine compound and a substituted orunsubstituted condensed polycyclic hydrocarbon compound.

The present invention further provides some processes for producing theabove-mentioned phthalocyanine crystal.

The present invention also provides an electrophotographicphotosensitive member comprising a support, and a photosensitive layerdisposed on the support and containing the above-mentionedphthalocyanine crystal.

The present invention further provides a process cartridge and anelectrophotographic apparatus respectively including the above-mentionedelectrophotographic photosensitive member.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an electrophotographic apparatusincluding an electrophotographic photosensitive member according to theinvention.

FIGS. 2 to 4 are schematic illustrations of electrophotographicapparatus including different types of process cartridges each includingan electrophotographic photosensitive member according to the invention.

FIG. 5 is an X-ray diffraction chart of chlorogallium phthalocyanineobtained in Synthesis Example 1.

FIG. 6 is an X-ray diffraction chart of hydroxygallium phthalocyanineobtained in Synthesis Example 2.

FIGS. 7-14 are X-ray diffraction charts of hydrogallium phthalocyaninecrystals obtained in Examples 1-8, respectively.

FIG. 15 is an X-ray diffraction chart of hydroxygallium phthalocyaninecrystal obtained in Comparative Example 1.

DETAILED DESCRIPTION OF THE INVENTION

The phthalocyanine crystal of the present invention comprises aphthalocyanine compound and a minor amount of substituted orunsubstituted condensed polycyclic hydrocarbon compound.

However, even if the phthalocyanine crystal of the present invention isheated up to the melting point of the substituted or unsubstitutedcondensed polycyclic hydrocarbon compound, the hydrocarbon compound isnot liberated from the phthalocyanine crystal. Further, even if thephthalocyanine crystal of the present invention is analyzed by liquidchromatography, the presence of the hydrocarbon compound is notdetected. From these facts, it is believed that the hydrocarbon compoundis not merely attached to the phthalocyanine compound but is firmly heldwithin the phthalocyanine crystal.

Examples of the condensed polycyclic hydrocarbon compound constitutingthe phthalocyanine crystal of the present invention may include:pentalene, indene, naphthalene, azulene, heptalene, biphenylene,indacene, acenaphthylene, fluorene, phenalene, phenanthrene, anthracene,fluoroanthene, pyrene, naphthacene, picene and perylene. Naphthalene isparticularly preferred.

Examples of the substituent optionally possessed by the above condensedpolycyclic hydrocarbon compound may include: alkyl groups, such asmethyl and ethyl; alkoxy groups, such as methoxyl and ethoxyl;alkylamino groups, such as dimethylamino and diethylamino; nitro, cyano,haloalkyl groups such as trifluoromethyl; halogen atoms, such aschorine, fluorine and iodine. Halogen atoms are particularly preferred.

Among the above-enumerated substituted or unsubstituted condensedpolycyclic hydrocarbon compounds, α-chloronaphthalene and naphthaleneare particularly preferred.

The substituted or unsubstituted condensed polycyclic hydrocarboncompound may preferably be contained in a proportion of 100-50000 ppmbased on the total weight of the phthalocyanine crystal. Outside thisrange, it becomes difficult to attain the remarkable effect of thepresent invention.

The phthalocyanine compound constituting the phthalocyanine crystal ofthe present invention may comprise any forms of phthalocyaninesinclusive of non-metallic phthalocyanine, metal phthalocyanines capableof having an axial ligand. The phthalocyanine compound can also have asubstituent and can have any crystal form. In order for thephthalocyanine crystal of the present invention to exhibit aparticularly excellent sensitivity characteristic, the phthalocyaninecompound may preferably comprise gallium phthalocyanine. Further, in thestate containing the substituted or unsubstituted condensed polycyclichydrocarbon compound, the phthalocyanine crystal of the presentinvention may preferably comprise hydroxygallium phthalocyanine crystalhaving crystal forms characterized by strong peaks at Bragg angles 2θ of7.4 deg. ±0.2 deg. and 28.2 deg. ±0.2 deg. (i.e., any crystal forms eachcharacterized by an X-ray diffraction pattern showing a peaktop in arange of 7.2-7.6 deg. and a peaktop in a range of 28.0-28.4 deg.)according to CuKα characteristic X-ray diffractometry. Among these, acrystal form characterized by strong peaks at Bragg angles 2θ±0.2 deg.of 7.3 deg., 24.9 deg. and 28.1 deg., and a crystal form characterizedby strong peaks at Bragg angles 2θ±0.2 deg. of 7.5 deg., 9.9 deg., 16.3deg., 18.6 deg., 25.1 deg. and 28.3 deg. (Herein, “±0.2 deg.” in “2θ±0.2deg.” represents an angle detection error generally recognized in X-raydiffractometry.)

The phthalocyanine crystal according to the present invention may beproduced through various processes, inclusive of: a process comprisingsubjecting a phthalocyanine compound to an acid pasting step includingdissolving or dispersing the phthalocyanine compound in an acid inmixture with a substituted or unsubstituted condensed polycyclichydrocarbon compound; a process comprising subjecting a phthalocyaninecompound to an acid pasting step including dissolving or dispersing aphthalocyanine compound in an acid to form a mixture, and adding themixture into a solution containing a substituted or unsubstitutedcondensed polycyclic hydrocarbon compound; and a process comprisingsubjecting a crystal transformation step including milling aphthalocyanine compound within a solvent containing a substituted orunsubstituted condensed polycyclic hydrocarbon compound.

Herein, the acid pasting step means a step of treating a phthalocyaninecompound including dissolving or dispersing the phthalocyanine compoundin an acid, adding the resultant solution or dispersion into an aqueousmedium to re-precipitate a phthalocyanine solid, optionally washing thephthalocyanine solid with an alkaline aqueous solution and washing thephthalocyanine solid with de-ionized water. The washing with deionizedwater may preferably be repeated until the after-washing water is causedto have a conductivity of at most 20 μS. The acid used may for examplebe sulfuric acid, hydrochloric acid and trifluoroacetic acid, and conc.sulfuric acid is particularly preferred. The acid may preferably be usedin an amount of 10-40 times the weight of the phthalocyanine compound.The phthalocyanine compound may preferably be dissolved or dispersed inthe acid at a temperature of at most 50° C. so as to avoid thedecomposition or reaction with the acid of the phthalocyanine compound.The substituted or unsubstituted condensed polycyclic hydrocarboncompound may preferably be used in an amount of 0.01-2 times the weightof the phthalocyanine compound in the case of dissolving or dispersingthe phthalocyanine compound in the acid already mixed with thesubstituted or unsubstituted condensed polycyclic hydrocarbon compound,or 0.01-10 times the weight of the phthalocyanine compound in the caseof adding the mixture of the phthalocyanine compound with the acid intoan aqueous medium containing the substituted or unsubstituted condensedpolycyclic hydrocarbon compound

As mentioned above, the phthalocyanine crystal according to the presentinvention can also be produced through a process comprising a step ofmilling a phthalocyanine compound within a solvent containing asubstituted or unsubstituted condensed polycyclic hydrocarbon compound.

The milling may be performed within a milling apparatus, such as a sandmill or a ball mill, wherein the phthalocyanine compound is milledtogether with dispersion media, such as glass beads, steel beads andalumina balls, in the presence of a solvent containing a substituted orunsubstituted condensed polycyclic hydrocarbon compound. The millingtime can vary depending on the milling apparatus used but may preferablybe on the order of 4-48 hours. It is preferred to check the crystal formby CuKα characteristic X-ray diffractometry for measuring the Braggangles at an interval of 4-8 hours each during the milling. Thedispersion medium may preferably be used in a weigh which is 10-50 timesthe phthalocyanine compound. Examples of the solvent used in the millingmay include: amide solvents, such as N,N-dimethylformamide,N,N-dimethylacetamide, N-methylformamide, N-methylacetamide andN-methylpropioamide; halide solvents, such as chloroform; ethersolvents, such as tetrahydrofuran; and sulfoxide solvents, such asdimethyl sulfoxide. The solvent may preferably be used in an amount of10-30 times the weight of the phthalocyanine compound. The substitutedor unsubstituted condensed polycyclic hydrocarbon compound maypreferably be used in an amount of 0.01-3 times the weight of thephthalocyanine compound.

The X-ray diffraction data referred to herein for determining thecrystal form of phthalocyanine crystals are based on data measured byX-ray diffractometry using CuK_(α) characteristic X-rays according tothe following conditions:

Apparatus: Full-automatic X-ray diffraction apparatus (“MXP18”,available from MAC Science K.K.)

X-ray tube (Target): Cu

Tube voltage: 50 kV

Tube current: 300 mA

Scanning method: 2θ/θ scan

Scanning speed: 2 deg./min.

Sampling interval: 0.020 deg.

Starting angle (2θ): 5 deg.

Stopping angle (2θ): 40 deg.

Divergence slit: 0.5 deg.

Scattering slit: 0.5 deg.

Receiving slit: 0.3 deg.

Curved monochromator: used.

Next, some embodiments of application of the phthalocyanine crystalaccording to the present invention as a charge-generating material inthe electrophotographic photosensitive member will be described.

The electrophotographic photosensitive member according to the presentinvention may have a laminar structure including a single photosensitivelayer containing both a charge-generating material and acharge-transporting material formed on an electroconductive support, oralternatively a laminar photosensitive layer including a chargegeneration layer containing a charge-generating material and a chargetransport layer containing a charge-transporting material formedsuccessively on an electroconductive support. The order of lamination ofthe charge generation layer and the charge transport layer can bereversed. It is however preferred that the charge generation layer isdisposed below the charge transport layer.

The electroconductive support may comprise any material exhibitingelectroconductivity, examples of which may include: metals, such asaluminum, aluminum alloys, copper, zinc, stainless steel, vanadium,molybdenum, chromium, titanium, nickel, indium, gold and platinum. Inaddition, it is also possible to use a support comprising a plasticsubstrate of, e.g., polyethylene, polypropylene, polyvinyl chloride,polyethylene terephthalate, acrylic resin or polyethylene fluoride, anda coating film formed thereon of a conductor such as aluminum, aluminumalloys, indium oxide, tin oxide or indium tin oxide, formed by vacuumdeposition; a support comprising a plastic substrate or a support asmentioned above further coated with a conductive coating layercomprising electroconductive particles of, e.g., aluminum, titaniumoxide, tin oxide, zinc oxide, carbon black or silver, together with anappropriate binder; a support comprising a plastic or paper impregnatedwith electroconductive particles, or a plastic support comprising anelectroconductive polymer.

It is possible to dispose an undercoating layer having a barrierfunction and an adhesive function between the support and thephotosensitive layer. The undercoating layer may comprise a material,such as polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methylcellulose, casein, polyamide (e.g., nylon 6, nylon 66, nylon 610,copolymer nylon and N-alkoxymethylated nylon), polyurethane, glue,aluminum oxide or gelatine. The under coating layer may preferably havea thickness of 0.1-10 μm, particularly 0.5-5 μm.

The single photosensitive layer may be formed by applying a coatingliquid comprising a mixture of the phthalocyanine crystal according tothe present invention as a charge-generating material and acharge-transporting material within a solution of a binder resin on thesupport optionally coated with the undercoating layer, etc., followed bydrying of the coating liquid.

For providing the laminated photosensitive layer, the charge generationlayer may be formed by application of a coating liquid formed bydispersing the phthalocyanine crystal according to the present inventionin a solution of an appropriate binder, followed by drying of thecoating liquid, but can also be formed by vacuum deposition of thephthalocyanine crystal.

The charge transport layer may be formed by application of a coatingliquid formed by dissolving a charge transporting material and a binderresin in a solvent, followed by drying of the coating liquid. Examplesof the charge-transporting material may include: various triarylaminecompounds, hydrazone compounds, stilbene compounds, pyrazolinecompounds, oxazole compounds, thiazole compounds, and triarylmethanecompounds.

Examples of the binder resin for providing the respective layers mayinclude: polyester, acrylic resin, polyvinylcarbazole, phenoxy resin,polycarbonate, polyvinyl butyral, polystyrene, polyvinyl acetate,polysulfone, polyarylate, polyvinylidene chloride, arylonitrilecopolymer and polyvinylbenzal.

For the formation of the photosensitive layers, various coating methodsmay be adopted, inclusive of dipping, spray coating, spinner coating,bead coating, blade coating and beam coating.

A photosensitive layer of a single-layer structure may preferably have athickness of 5-40 μm, particularly 10-30 μm. In a laminatedphotosensitive layer structure, the charge generation layer maypreferably have a thickness of 0.01-10 μm, particularly 0.1-3 μm, andthe charge transport layer may preferably have a thickness of 5-40 μm,particularly 10-30 μm.

The charge-generating material may preferably be contained in 20-90 wt.%, more preferably 50-80 wt. %, of the charge generation layer. Thecharge-transporting material may preferably be contained in 20-80 wt. %,more preferably 30-70 wt. % of the charge transport layer. In the caseof a single photosensitive layer, the charge-generating material maypreferably contained in 3-30 wt. %, and the charge-transporting materialmay preferably be contained in 30-70 wt. %, respectively of thephotosensitive layer.

The phthalocyanine crystal of the present invention may be used as sucha charge-generating material and can be used in mixture with anothercharge-generating material. In the latter case, the phthalocyaninecrystal may preferably occupy at least 50 wt. % of the total chargegenerating materials.

The photosensitive layer can be further coated with a protective layeras desired. Such a protective layer may be formed in a thickness ofpreferably 0.05-20 μm by application of a solution in an appropriatesolvent of a resin, such as polyvinyl butyral, polyester, polycarbonate(polycarbonate Z, modified polycarbonate, etc.), nylon, polyimide,polyarylate, polyurethane, styrene-butadiene copolymer, ethylene-acrylicacid copolymer, styrene-acrylonitrile copolymer, or curable resinprecursor, followed by drying and optional curing. The protective layercan further contain electroconductive particles of, e.g., metal oxides,such as tin oxide, an ultraviolet absorber, etc.

Next, some description will be made on the electrophotographic apparatusaccording to the present invention.

Referring to FIG. 1, a photosensitive member 1 in the form of a drum isrotated about an axis 1 a at a prescribed peripheral speed in thedirection of the arrow shown inside of the photosensitive member 1. Theperipheral surface of the photosensitive member 1 is uniformly chargedby means of a primary charger 2 to have a prescribed positive ornegative potential. At an exposure part 3, the photosensitive member 1is imagewise exposed to light L (as by slit exposure or laserbeam-scanning exposure) by using an image exposure means (not shown),whereby an electrostatic latent image is successively formedcorresponding to the exposure pattern on the surface of thephotosensitive member 1. The thus formed electrostatic latent image isdeveloped by using a developing means 4 to form a toner image. The tonerimage is successively transferred to a transfer(-receiving) material 9which is supplied from a supply part (not shown) to a position betweenthe photosensitive member 1 and a transfer charger 5 in synchronism withthe rotation speed of the photosensitive member 1, by means of a coronatransfer charger 5. The transfer material 9 carrying the toner imagethereon is separated from the photosensitive member 1 to be conveyed toa fixing device 8, followed by image fixing to print out the transfermaterial 9 as a copy outside the electrophotographic apparatus. Residualtoner particles remaining on the surface of the photosensitive member 1after the transfer operation are removed by a cleaning means 6 toprovide a cleaned surface, and residual charge on the surface of thephotosensitive member 1 is erased by a pre-exposure means 7 to preparefor the next cycle.

FIG. 2 shows an electrophotographic apparatus wherein anelectrophotographic photosensitive member 1, a charging means 2 and adeveloping means 4 are integrally stored in a container 20 to form aprocess cartridge, which is detachably mountable to a main assembly ofthe electrophotographic apparatus by the medium of a guiding means, suchas a rail of the main assembly. A cleaning means 6 may be disposed asshown or not disposed within the container 20.

FIGS. 3 and 4 show other embodiments of the electrophotographicapparatus according to the present invention including different formsof process cartridges wherein a contact charging member 10 supplied witha voltage as a charging means is caused to contact a photosensitivemember 1 to charge the photosensitive member 1. In the apparatus ofFIGS. 3 and 4, toner images on the photosensitive member 1 aretransferred onto a transfer material P also by means of a contactcharging member 23. More specifically, a contact charging member 23supplied with a voltage is caused to contact a transfer material,whereby a toner image on the photosensitive member 1 is transferred ontothe transfer material 9.

Further, in the apparatus of FIG. 4, at least the photosensitive member1 and the contact charging member 10 are stored within a first container21 to form a first process cartridge, and at least the developing means4 is stored within a second container 22 to form a second processcartridge; so that the first and second process cartridges aredetachably mountable to the main assembly of the electrophotographicapparatus. A cleaning means 6 may be disposed as shown or not disposedwithin the container 21. In the case where the electrophotographicapparatus constitutes a copying machine or a printer, the exposure lightL may be provided as reflected light or transmitted light from anoriginal, or alternatively provided as image-carrying illumination lightformed by reading an original by a sensor, converting the read data intosignals and driving a laser beam scanner, an LED array or a liquidcrystal shutter array.

Hereinbelow, the present invention will be described more specificallywith reference to Examples and Comparative Examples wherein “parts” and“%” used for describing a relative amount of a component or a materialare by weight unless specifically noted otherwise.

SYNTHESIS EXAMPLE 1

72 parts of o-phthalonitrile, 25 parts of gallium trichloride and 350parts of quinoline were reacted with each other for 4 hours at 200° C.in a nitrogen atmosphere, followed by filtration at 130° C. to recoverthe product. The product was washed in dispersion withinN,N-dimethylformamide at 140° C. for 2 hours, followed by filtration,washing with methanol and drying to obtain 32 parts (yield: 38.0%) ofchlorogallium phthalocyanine crystal. The chlorogallium phthalocyaninecrystal (represented by C₃₂H₁₆ClGaN₈) exhibited a powdery X-raydiffraction pattern as shown in FIG. 5 and the following results ofelementary analysis.

Element Calculated (%) Measured (%) C 62.2 62.4 H 2.6 2.6 N 18.1 18.2 Cl5.7 5.9

SYNTHESIS EXAMPLE 2

15 parts of the chlorogallium phthalocyanine prepared in SynthesisExample 1 was dissolved in 300 parts of conc. sulfuric acid cooled at15° C., and the resultant solution was added dropwise into 2000 parts oficed water under stirring to cause re-precipitation, followed byfiltration. The precipitate was washed in dispersion first within 2%ammonia water and then four times within deionized water, and then driedin vacuum at 40° C. to obtain 13 parts of hydroxygallium phthalocyaninecrystal. The hydroxygallium phthalocyanine crystal (represented byC₃₂H₁₇GaN₈O) exhibited a powdery X-ray diffraction pattern as shown inFIG. 6 and the following results of elementary analysis.

Element Calculated (%) Measured (%) C 64.1 63.2 H 2.9 3.2 N 18.7 18.3 Cl0.0 0.0

EXAMPLE 1

15 parts of the chlorogallium phthalocyanine prepared in SynthesisExample 1 was dissolved in a mixture of 300 parts of conc. sulfuric acidand 1.5 parts (corresponding to 10% of the chlorogallium phthalocyanine)of α-chloronaphthalene (purity>85%, available from Tokyo Kasei KogyoK.K.) cooled at 15° C., and the resultant solution was added dropwiseinto 2000 parts of iced water under stirring to cause re-precipitation,followed by filtration. The precipitate was washed in dispersion firstwithin 2% ammonia water and then four times within deionized water, andthen dried in vacuum at 40° C. to obtain 13 parts of hydroxygalliumphthalocyanine crystal, which exhibited a powdery X-ray diffractionpattern as shown in FIG. 7.

EXAMPLE 2

15 parts of the chlorogallium phthalocyanine prepared in SynthesisExample 1 was dissolved in 300 parts of conc. sulfuric acid cooled at15° C., and the resultant solution was added dropwise into a mixture of2000 parts of iced water and 15 parts (corresponding to 100% of thechlorogallium phthalocyanine) under stirring to cause re-precipitation,followed by filtration. The precipitate was washed in dispersion firstwithin 2% ammonia water and then four times within deionized water, andthen dried in vacuum at 40° C. to obtain 13 parts of hydroxygalliumphthalocyanine crystal, which exhibited a powdery X-ray diffractionpattern as shown in FIG. 8.

EXAMPLE 3

5 parts of the hydroxygallium phthalocyanine prepared in Example 1 and95 parts of N,N-dimethylformamide were milled together with 150 parts of1 mm-dia. glass beads for 20 hours at room temperature (24° C.) in aball mill. The solid matter was recovered from the resultant dispersion,sufficiently washed with tetrahydrofuran, and dried, to obtain 4.5 partsof hydroxygallium phthalocyanine crystal. The hydroxygalliumphthalocyanine crystal (as represented by C₃₂H₁₇GaN₈O for convenience)exhibited an X-ray diffraction pattern as shown in FIG. 9 and thefollowing results of elementary analysis. The measured value of Clcontent indicated that 6845 ppm of α-chloronaphthalene was contained inthe crystal.

Element Calculated (%) Measured (%) C 64.1 63.5 H 2.9 3.0 N 18.7 18.3 Cl0.0 0.150

EXAMPLE 4

The hydroxygallium phthalocyanine prepared in Example 2 was subjected tomilling and post-treatments similarly as in Example 3. The recoveredhydroxygallium phthalocyanine crystal (as represented by C₃₂H₁₇GaN₈O)exhibited an X-ray diffraction pattern as shown in FIG. 10 and thefollowing results of elementary analysis. The measured value of Clcontent indicated that 7301 ppm of α-chloronaphthalene was contained inthe crystal.

Element Calculated (%) Measured (%) C 64.1 63.9 H 2.9 3.0 N 18.7 18.4 Cl0.0 0.160

EXAMPLE 5

5 parts of the hydroxygallium phthalocyanine prepared in SynthesisExample 2, 95 parts of N,N-dimethylformamide and 0.5 part ofα-chloronaphthalene were milled together with 150 parts of 1 mm-dia.glass beads for 20 hours at room temperature (24° C.) in a ball mill.The solid matter was recovered from the resultant dispersion,sufficiently washed with tetrahydrofuran, and dried, to obtain 4.5 partsof hydroxygallium phthalocyanine crystal. The hydroxygalliumphthalocyanine crystal (as represented by C₃₂H₁₇GaN₈0) exhibited anX-ray diffraction pattern as shown in FIG. 11 and the following resultsof elementary analysis. The measured value of Cl content indicated that3057 ppm of α-chloronaphthalene was contained in the crystal.

Element Calculated (%) Measured (%) C 64.1 63.4 H 2.9 3.0 N 18.7 18.6 Cl0.0 0.067

EXAMPLE 6

5 parts of the hydroxygallium phthalocyanine prepared in SynthesisExample 2, 95 parts of N,N-dimethylformamide and 5 parts ofα-chloronaphthalene were milled together with 150 parts of 1 mm-dia.glass beads for 20 hours at room temperature (24° C.) in a ball mill.The solid matter was recovered from the resultant dispersion,sufficiently washed with tetrahydrofuran, and dried, to obtain 4.5 partsof hydroxygallium phthalocyanine crystal. The hydroxygalliumphthalocyanine crystal (as represented by C₃₂H₁₇GaN₈O) exhibited anX-ray diffraction pattern as shown in FIG. 12 and the following resultsof elementary analysis. The measured value of Cl content indicated that7073 ppm of α-chloronaphthalene was contained in the crystal. As aresult of TG-GC/MS (thermogravimetry-gas chromatography/massspectrometry) analysis in the range of 25° C.-500° C. (by using a TG-MSsimultaneous measurement apparatus, available from K.K. ShimadzuSeisakosho), the crystal exhibited 6474 ppm of α-chloronaphthalene, 155ppm of naphthalene, and 2.03% of N,N-dimethylformamide. Theα-chloronaphthalene content was in good agreement with that calculatedfrom the chlorine (Cl) content.

Element Calculated (%) Measured (%) C 64.1 63.4 H 2.9 3.0 N 18.7 18.6 Cl0.0 0.155

EXAMPLE 7

5 parts of the hydroxygallium phthalocyanine prepared in SynthesisExample 2, 95 parts of N,N-dimethylformamide and 0.5 part of naphthalenewere milled together with 150 parts of 1 mm-dia. glass beads for 20hours at room temperature (24° C.) in a ball mill. The solid matter wasrecovered from the resultant dispersion, sufficiently washed withtetrahydrofuran, and dried, to obtain 4.5 parts of hydroxygalliumphthalocyanine crystal. The hydroxygallium phthalocyanine crystal (asrepresented by C₃₂H₁₇GaN₈O) exhibited an X-ray diffraction pattern asshown in FIG. 13 and the following results of elementary analysis.Further, as a result of the TG-GC/MS analysis (25-500° C.), the crystalexhibited 1500 ppm of naphthalene and 2.00% of N,N-dimethylformamide.

Element Calculated (%) Measured (%) C 64.1 63.4 H 2.9 3.0 N 18.7 18.7 Cl0.0 0.0

EXAMPLE 8

5 parts of the hydroxygallium phthalocyanine prepared in SynthesisExample 2, 95 parts of N,N-dimethylformamide and 5 parts of naphthalenewere milled together with 150 parts of 1 mm-dia. glass beads for 20hours at room temperature (24° C.) in a ball mill. The solid matter wasrecovered from the resultant dispersion, sufficiently washed withtetrahydrofuran, and dried, to obtain 4.5 parts of hydroxygalliumphthalocyanine crystal. The hydroxygallium phthalocyanine crystal (asrepresented by C₃₂H₁₇GaN₈0) exhibited an X-ray diffraction pattern asshown in FIG. 14 and the following results of elementary analysis.Further, as a result of the TG-GC/MS analysis (25-500° C.), the crystalexhibited 2840 ppm of naphthalene and 2.00% of N,N-dimethylformamide.

Element Calculated (%) Measured (%) C 64.1 63.4 H 2.9 3.0 N 18.7 18.7 Cl0.0 0.0

COMPARATIVE EXAMPLE 1

The hydroxygallium phthalocyanine prepared in Synthesis Example 1 wassubjected to milling and post-treatments similarly as in Example 3. Therecovered hydroxygallium phthalocyanine crystal (represented byC₃₂H₁₇GaN₈O) exhibited an X-ray diffraction pattern as shown in FIG. 15and the following results of elementary analysis. Further, as a resultof the TG-GC/MS analysis (25-500° C.), the crystal exhibited 3.38% ofN,N-dimethylformamide.

Element Calculated (%) Measured (%) C 64.1 63.6 H 2.9 3.0 N 18.7 18.9 Cl0.0 0.0

EXAMPLE 9

50 parts of titanium oxide powder coated with tin oxide containing 10%of antimony oxide, 25 parts of resol-type phenolic resin, 20 parts ofmethyl cellosolve, 5 parts of methanol and 0.002 part of silicone oil(polydimethylsiloxane-polyoxyalkylene copolymer, average molecularweight=3000), were dispersed for 2 hours in a sand mill containing 1mm-dia. glass beads, to prepare an electroconductive paint. An aluminumcylinder (of 30 mm in diameter) was coated by dipping within theabove-prepared electroconductive paint, followed by drying at 140° C.for 30 min. to form a 15 μm-thick electroconductive layer.

The aluminum cylinder was further coated by dipping within a solution of5 parts of 6-66-610-12 quaternary polyamide copolymer resin in a solventmixture of 70 parts of methanol and 25 parts of butanol, followed bydrying, to form a 0.7 μm-thick undercoating layer.

Separately, 2.5 part of the gallium phthalocyanine crystal prepared inExample 3 and 1 part of polyvinyl butyral resin (“S-LEC BX-1”, availablefrom Sekisui Kagaku Kogyo K.K.), were added to 70 parts ofcyclohexanone, and the mixture was subjected to 3 hours of dispersion ina sand mill containing 1 mm-dia. glass beads and then diluted with 100parts of ethyl acetate to obtain a paint. The paint was applied bydipping onto the undercoating layer and dried at 120° C. for 10 min. toform a 0.2 μm-thick charge generation layer.

Then, 10 parts of a charge-transporting material of the followingstructural formula:

and 10 pats of polycarbonate resin (“IUPILON Z-200”, available fromMitsubishi Gas Kagaku K.K.) were dissolved in 60 parts ofmonochlorobenzene to form a coating solution, which was then applied bydipping on the above-formed charge generation layer on the aluminumcylinder and dried at 120° C. for 60 min, to form a 17 μm-thick chargetransport layer, thus providing an electrophotographic photosensitivemember.

EXAMPLES 10-14

Five electrophotographic photosensitive members were prepared in thesame manner as in Example 9 except that the gallium phthalocyaninecrystal of Example 3 was replaced by the gallium phthalocyanine crystalsof Examples 4-8, respectively.

COMPARATIVE EXAMPLE 2

A comparative electrophotographic photosensitive member was prepared inthe same manner as in Example 9 except that the gallium phthalocyaninecrystal of Example 3 was replaced by the gallium phthalocyanine crystalof Comparative Example 1.

Each of the electrophotographic photosensitive members prepared inExamples 9-14 and Comparative Example 2 was evaluated with respect tosensitivity and image defects of black spots and fog by incorporating itinto a process cartridge of a commercially available laser beam printer(“LBP-1760”, mfd. by Canon K.K.) and incorporating the process cartridgein the printer after remodeling for allowing light quantity change. Thesensitivity measurement was performed by setting the charging conditionso as to provide a dark-part potential of −600 volts and measuring alight quantity required for lowering the potential to −140 volts.

Then, the photosensitive member incorporated in the printer wassubjected to evaluation of images formed at an initial stage in a hightemperature/high humidity environment of 35° C./80% RH. The imageevaluation was evaluated by the state of occurrence of image defectsinclusive of black spots and fog due to charging failure according tothe following standards.

A: No black spots or fog observed with eyes.

C: Black spots or fog observed with eyes.

The results of the evaluation are inclusively shown in the followingTable 1.

TABLE 1 Example Sensitivity (μJ/cm²) Image evaluation  9 0.36 A 10 0.48A 11 0.34 A 12 0.33 A 13 0.38 A 14 0.34 A Comp. 2 0.56 C

Each of the photosensitive members prepared in Examples 11, 12 and 14,and Comparative Example 2 (identical to those evaluated in the abovetest but in separately as-produced state) was incorporated in a processcartridge and then in a commercially available printer (“LBP-1760”)(without the above remodeling) for measurement of a light-part potential(Vl) in an initial stage, a continuous image formation on 5000 sheetsand measurement of a change in light-part potential (Δ|Vl|) after thecontinuous image formation. The results are inclusively shown in Table 2below. Incidentally, Δ|Vl|=+10 volts means an increase in absolute valueof the light-part potential (e.g., a change rom Vl=−180 volts to Vl=−190volts).

TABLE 2 Example Initial V1 (volts) Δ|V1| (volts) 11 −180 +10 12 −170  +514 −180 +10 Comp. 2 −270 +40

As described above, according to the present invention, a phthalocyaninecrystal formed by doping a phthalocyanine compound with a minor mount ofa substituted or unsubstituted condensed polycyclic hydrocarbon compoundis provided, and by incorporating the phthalocyanine crystal in aphotosensitive layer, it is possible to provide an electrophotographicphotosensitive member exhibiting a high sensitivity in a semiconductorwavelength region and a potential stability in repetitive use, andfurther providing images with less image defects, particularly lessblack spots in a reversal development scheme.

What is claimed is:
 1. A process for producing a phthalocyanine crystalcomprising a phthalocyanine compound and a substituted or unsubstitutedcondensed polycyclic hydrocarbon compound, said process comprisingsubjecting a phthalocyanine compound to an acid pasting step includingdissolving or dispersing the phthalocyanine compound in an acid whichhas been mixed with a substituted or unsubstituted condensed polycyclichydrocarbon compound, the phthalocyanine compound being galliumphthalocyanine, the gallium phthalocyanine being hydroxgalliumphthalocyanine, and having a crystal form characterized by strong peaksat Bragg angles 2θ of 7.4 deg.+0.2 deg. and 28.2 deg.+0.2 deg.
 2. Aprocess for producing a phthalocyanine crystal comprising aphthalocyanine compound and a substituted or unsubstituted condensedpolycyclic hydrocarbon compound, said process comprising subjecting aphthalocyanine compound to an acid pasting step including dissolving ordispersing a phthalocyanine compound in an acid to form a mixture, andadding the mixture into a solution containing a substituted orunsubstituted condensed polycyclic hydrocarbon compound, thephthalocyanine compound being gallium phthalocyanine, the galliumphthalocyanine being hydroxgallium phthalocyanine, and having a crystalform characterized by strong peaks at Bragg angles 2θ of 7.4 deg.+0.2deg. and 28.2 deg.+0.2 deg.
 3. A process for producing a phthalocyaninecrystal comprising a phthalocyanine compound and a substituted orunsubstituted condensed polycyclic hydrocarbon compound, said processcomprising subjecting a crystal transformation step including milling aphthalocyanine compound within a solvent containing a substituted orunsubstituted condensed polycyclic hydrocarbon compound, thephthalocyanine compound being gallium phthalocyanine, the galliumphthalocyanine being hydroxgallium phthalocyanine, and having a crystalform characterized by strong peaks at Bragg angles 2θ of 7.4 deg.+0.2deg. and 28.2 deg.+0.2 deg.
 4. The process according to claim 1, whereinthe substituted or unsubstituted condensed polycyclic hydrocarboncompound is a halo-substituted condensed polycyclic hydrocarboncompound.
 5. The process according to claim 4, wherein thehalo-substituted condensed polycyclic hydrocarbon compound isα-chloronaphthalene.
 6. The process according to claim 1, wherein thesubstituted or unsubstituted condensed polycyclic hydrocarbon compoundis naphthalene.
 7. The process according to claim 2, wherein saidsubstituted or unsubstituted condensed polycyclic hydrocarbon compoundis a halo-substituted condensed polycyclic hydrocarbon compound.
 8. Theprocess according to claim 7, wherein the halo-substituted condensedpolycyclic hydrocarbon compound is α-chloronaphthalene.
 9. The processaccording to claim 2, wherein the substituted or unsubstituted condensedpolycyclic hydrocarbon compound is napthalene.
 10. The process accordingto claim 3, wherein the substituted or unsubstituted condensedpolycyclic hydrocarbon compound is a halo-substituted condensedpolycyclic hydrocarbon compound.
 11. The process according to claim 10,wherein the halo-substituted condensed polycyclic hydrocarbon compoundis α-chloronaphthalene.
 12. The process according to claim 3, whereinthe substituted or unsubstituted condensed polycyclic hydrocarboncompound is naphthalene.
 13. The process according to claim 1, whereinthe acid is concentrated sulfuric acid.
 14. The process according toclaim 1, wherein the acid is used in an amount of 10-40 times the weightof the phthalocyanine compound.
 15. The process according to claim 1,wherein the phthalocyanine compound is dissolved in the acid at atemperature of at most 50° C.
 16. The process according to claim 1,wherein said substituted or unsubstituted condensed polycyclichydrocarbon compound is used in an amount of 0.01-2 times the weight ofthe phthalocyanine compound.
 17. The process according to claim 2,wherein said acid is concentrated sulfuric acid.
 18. The processaccording to claim 2, wherein the acid is used in a mount of 10-40 timesthe weight of the phthalocyanine compound.
 19. The process according toclaim 2, wherein the phthalocyanine compound is dissolved in the acid ata temperature of at most 50° C.
 20. The process according to claim 2,wherein the substituted or unsubstituted condensed polycyclichydrocarbon compound is used in a amount of 0.01-10 times the weight ofthe phthalocyanine compound.
 21. The process according to claim 3,wherein the solvent is N,N-dimethyl formamide.
 22. The process accordingto claim 3, wherein the solvent is used in an amount of 10-30 times theweight of the phthalocyanine compound.
 23. The process according toclaim 3, wherein the substituted or unsubstituted condensed polycyclichydrocarbon compound is used in an amount of 0.01-3 times the weight ofthe phthalocyanine compound.